1. Field of the Invention
This invention rlates to an apparatus and a method for forming the leads of semiconductor devices utilized in manufacturing semiconductor devices.
2. Description of the Related Art
FIG. 1 shows a conventional lead-forming device, which includes a press 1. Connected to this press 1 are a conveying rail 3 for conveying lead frames 9, a discharge cylinder 6 for discharging from the press 1 the products formed therein, a product storage section 7 for storing the products discharged from the press 1, and a discharge chute 10 for discharging the remnants of lead frames left over from punching of the products. Arranged beside the conveying rail 3 is a magazine 8 for storing a multitude of lead frames 9 for lead forming. Semiconductor chips (not shown) are mounted on these lead frames 9 and resin-sealed. As shown in FIG. 2, the press 1 includes a mold composed of an upper mold half 4 and a lower mold half 5, and a hydraulic cylinder 2.
The operation of this conventional device will now be described. After the resin-sealed lead frame 9 is taken out of the magazine 8, it is conveyed along the conveying rail 3 and is set on the lower mold half 5. The hydraulic cylinder 2 then causes the upper mold half 4 to be lowered so that the leads of the lead frame 9 may be formed, i.e., the tie-bars connecting the adjacent leads may be cut and the leads bent. The semiconductor device thus formed is discharged from the press 1 by the discharge cylinder 6 and stored in the product storage section 7, the remnants of the lead frame 9 being discharged through the discharge chute 10.
It is to be noted, however, that the resin-sealing of the semiconductor chips on the lead frame 9 normally involves the generation of resin burrs between the adjacent leads. If the lead frame 9 having these resin burrs were lead-formed as it is, the resin would be punched into the leads, resulting in poor contact of the latter. It is consequently necessary to remove the resin burrs from between the leads of the lead frames, which increases the number of manufacturing processes.